How much do you spend on OpenAI integration?

Question for people using OpenAI to add features to their Discourse forum: how much are you spending on the API access?

It might be good to have the number as a proportion of your hosting costs - a bigger forum costs more to host but will make more use of the API too. A tiny forum will cost little, in both cases.

This is just idle curiosity on my part, but it might be a useful calibration for people thinking of adding OpenAI features.